1. Field of the Invention
The disclosure generally relates to a communication device, and more particularly, relates to a communication device comprising an antenna system with high isolation.
2. Description of the Related Art
In recent years, the smart phone has become one of the most indispensable mobile communication devices for modern people to use in their daily lives, allowing for convenience and timeliness. A user usually demands a variety of functions for smart phones. For example, the smart phone is required to perform MIMO (Multi-Input Multi-Output) operations by multiple antennas therein to accelerate data transmission, or is required to have functions of dual-SIM, dual-standby, and dual-talk. Thus, while a first SIM (Subscriber Identity Module) card of the smart phone is transmitting data through an antenna, a second SIM card of the smart phone is capable of transmitting voice signals through another antenna; bringing convenience to a user with a dual-SIM smart phone. As for antenna systems in mobile communication devices, an antenna system with multiple antennas operating in a same band must be disposed in a small space of a mobile communication device (e.g., a smart phone). Since the antennas are very close to each other, mutual coupling and interference therebetween are enhanced, thereby degrading the performance of the antenna system. Thus, maintaining a high amount of isolation and reducing mutual coupling and interference between antennas are critical challenges for antenna designers.
Accordingly, there is a need to design a new antenna system with multiple antennas, which may be applied to a mobile communication device. Such an antenna system would not only have high isolation between antennas therein but also maintain good radiation efficiency to meet practical application requirements.